STYRACER. SILVA OF NORTH AMERICA. 23 
MOHRODENDRON DIPTERUM. 
Snowdrop Tree. Silver Bell Tree. 
CoroLia divided nearly to the base; ovary usually 2-celled. Fruit 2-winged. 
Leaves ovate or sometimes slightly obovate. 
Mohrodendron dipterum, Britton, Garden and Forest, 
vi. 463 (1893). 
Halesia diptera, Ellis, Phil. Trans. li. 932, t. 22, f. B 
Syst. iv. 7. — Spach, Hist. Vég. ix. 426.— A. de Candolle, 
Prodr. viii. 270. — Miers, Contrib. i. 193. — Payer, Organ. 
Compt. 537, t. 126, £. 20-28. — Chapman, FV. 271. — 
(1761). — Linneus, Spec. ed. 2, 636. — Marshall, Arbust. 
Am. 57.— Lamarck, Dict. iii. 66. — Willdenow, Berl. 
Baumz. 138; Spec. ii. 849; Hnum. 496. — Cavanilles, 
Diss. vi. 338, t. 187. — Michaux, Fl. Bor.-Am. ii. 40. — 
Koch, Dendr. ii. 201. — Lauche, Deutsche Dendr. ed. 2, 
220.— Gray, Syn. Fl. N. Am. ii. pt. i. 71. — Sargent, 
Forest Trees N. Am. 10th Census U. S. ix. 105.— 
Koehne, Deutsche Dendr. 486. 
Persoon, Syn. ii. 4. — Nouveau Duhamel, v. 144. — Pursh, Halesia reticulata, Buckley, Proc. Phil. Acad. 1860, 444. 
Fl. Am. Sept. ii. 450. — Nuttall, Gen. ii. 83.— Elliott, Mohria diptera, Britton, Garden and Forest, vi. 434 
Sk. i, 508. — Hayne, Dendr. Fl. 66.— Loddiges, Bot. (1893). 
Cab. xii. t. 1172. —Sprengel, Syst. iii. 84. Don, Gen. Carlomohria diptera, Greene, Hrythea, i. 246 (1893). 
A tree, rarely thirty feet in height, with a short trunk occasionally eight or ten inches in diameter, 
and horizontal branches which form a low broad head ;* or more often a shrub sending up from the 
ground numerous stout spreading stems. The bark of the trunk, which varies from a third to half an 
inch in thickness, is brown tinged with red, and divided by irregular longitudinal often broad fissures, 
the surface exfoliating into small thin appressed scales. The branchlets, when they first appear, are hight 
green and more or less coated with pale pubescence, which generally disappears during the summer; in 
their first winter they are usually glabrous, orange-color or reddish brown, lustrous and marked with 
the large elevated obcordate leaf-scars; in their second year the bark becomes dark red-brown, often 
separating into thread-like scales, and during the following season begins to divide into irregular pale 
longitudinal fissures. The winter-buds are axillary, a sixteenth of an inch long, ovate, and obtuse, 
with broadly ovate acute light red puberulous scales ; at maturity those of the inner ranks are strap- 
shaped, scarious, and a quarter of an inch long. The end of the branch dies before a terminal bud is 
formed and remains during the winter as a dark withered stub at the side of the upper axillary bud 
which the following spring prolongs the branch. The leaves are ovate, sometimes slightly obovate, 
acuminate, wedge-shaped or rounded at the base, and remotely serrate with minute callous teeth; when 
they unfold they are coated with pale tomentum on the lower surface, and are puberulous on the 
upper surface; at maturity they are thin, ight green, glabrous above except along the narrow midribs, 
pubescent below, four to five inches long and an inch and a half to three inches wide, with conspic- 
uous pale arcuate veins, reticulated veinlets, and stout petioles two thirds of an inch in length. The 
flowers, which open from the middle of March to the end of April, are produced in fascicles or short 
racemes, and are borne on slender pedicels an inch and a half or two inches long, and developed in the 
axils of obovate or acute puberulous caducous bracts often a quarter of an inch long. The calyx is 
inversely pyramidal, with minute triangular teeth. The corolla is nearly an inch long, puberulous on the 
outer surface, and divided nearly to the base into slightly obovate spreading divisions about as long as 
the stamens, which are usually eight, although they vary in number from eight to sixteen ; the filaments 
are covered with pale hairs, and are sometimes free from the corolla. 
four-celled, and, like the exserted stigma, is coated with pale tomentum. The fruit is oblong, com- 
pressed, an inch and a half to two inches long and often nearly an ich wide, with two broad wings, 
1 W. Bartram, Travels, 410. 
The ovary is usually two, rarely 
